Compound and method for treating myotonic dystrophy

ABSTRACT

Provided are 9-base morpholino antisense compounds targeted to polyCUG repeats in the 3′UTR region of dystrophia myotonica protein kinase (DMPK) mRNA, and related methods for treating myotonic dystrophy DM1.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.14/464,561, filed on Aug. 20, 2014, which is a continuation of U.S.application Ser. No. 14/038,314, filed on Sep. 26, 2013, now U.S. Pat.No. 8,835,402, which is a continuation of U.S. application Ser. No.13/101,942, filed on May 5, 2011, now abandoned, which is acontinuation-in-part of U.S. application Ser. No. 12/493,140, filed onJun. 26, 2009, now abandoned, the contents of each of which isincorporated by reference in its entirety.

STATEMENT REGARDING SEQUENCE LISTING

The sequence listing associated with this application is provided intext format in lieu of a paper copy, and is hereby incorporated byreference into the specification. The name of the text file containingthe Sequence Listing is 606266_SPT-8083CON4_ST25.txt. The text file isabout 13.4 KB, was created on Oct. 18, 2018, and is being submittedelectronically via EFS-web.

FIELD OF THE INVENTION

The present invention relates to antisense oligonucleotides targeted topolyCUG repeats in the 3′UTR region of dystrophia myotonica proteinkinase (DMPK) mRNA, and methods for treating myotonic dystrophy DM1.

BACKGROUND OF THE INVENTION

Myotonic dystrophy type 1 (DM1) and type 2 (DM2) are associated withlong polyCUG and polyCCUG repeats in the 3′-UTR and intron 1 regions ofthe transcript dystrophia myotonica protein kinase (DMPK) and zincfinger protein 9 (ZNF9), respectively (Wheeler and Thornton 2007). Whilenormal individuals have as many as 30 CTG repeats, DM1 patients carry alarger number of repeats ranging from 50 to thousands. The severity ofthe disease and the age of onset correlates with the number of repeats.Patients with adult onsets show milder symptoms and have less than 100repeats, juvenile onset DM1 patients carry as many as 500 repeats andcongenital cases usually have around a thousand CTG repeats. Theexpanded transcripts containing CUG repeats form a secondary structure,accumulate in the nucleus in the form of nuclear foci and sequesterRNA-binding proteins (RNA-BP).

Several RNA-BP have been implicated in the disease, includingmuscleblind-like (MBNL) proteins and CUG-binding protein (CUGBP). MBNLproteins are homologous to Drosophila muscleblind (Mbl) proteinsnecessary for photoreceptor and muscle differentiation. MBNL and CUGBPhave been identified as antagonistic splicing regulators of transcriptsaffected in DM1 such as cardiac troponin T (cTNT), insulin receptor (IR)and muscle-specific chloride channel (CIC-1).

Myotonic dystrophy type 2 (DM2) is associated with repeats in the firstintron of the ZNF9 gene on chromosome 3. CNBP (ZNF9) is the only geneknown to be associated with myotonic dystrophy type 2. CNBP intron 1contains a complex repeat motif, (TG)n(TCTG)n(CCTG)n, and expansion ofthe CCTG repeat causes DM2. The number of CCTG repeats in expandedalleles can range from approximately 75 to more than 11,000, with a meanof approximately 5000 repeats.

DM1 and DM2 are associated with a variety of serious pathologiesincluding muscle abnormalities and weakness, and in the heart,conduction abnormalities.

SUMMARY OF THE INVENTION

The present invention is based on the unexpected antisense activity of9-base phosphorodiamidate morpholino oligomers (PMOs), relative, forexample, to longer PMOs, for reducing or ameliorating one or moresymptoms of myotonic dystrophy type 1 (DM1) or type 2 (DM2). These9-base antisense oligomers described herein can employ a variety ofPMO-based chemistries, including PMO, PMO+, PPMO, and PPMO+ chemistries,as described herein.

Embodiments of the present invention therefore include antisensecompounds for treating myotonic dystrophy type 1 (DM1), comprising amorpholino antisense oligonucleotide of 9 bases, where the 9 bases arecomplementary to polyCUG repeats in the 3′UTR region of dystrophiamyotonica protein kinase (DMPK) mRNA. In certain embodiments, theoligonucleotide is a phosphorodiamidate morpholino oligonucleotide(PMO). In some embodiments, at least one and up to about 1 per every 2intersubunit linkage(s) of the oligonucleotide contains a pendantcationic group. In specific embodiments, the cationic group comprises anoptionally substituted piperazino group (PMO+). In certain embodiments,the oligonucleotide is conjugated to a cell-penetrating peptide, such asan arginine-rich peptide (PPMO or PPMO+).

Also included are methods of treating myotonic dystrophy DM1 in amammalian subject, comprising administering to the subject, a morpholinoantisense compound of 9 bases, where the 9 bases are complementary topolyCUG repeats in the 3′UTR region of dystrophia myotonica proteinkinase (DMPK) mRNA, and optionally repeating said administering at leastonce every one week to 3 months. In some embodiments, at least one andup to about 1 per every 2 intersubunit linkage(s) of the oligonucleotidecontains a pendant cationic group. In specific embodiments, the cationicgroup comprises an optionally substituted piperazino group. In certainembodiments, the oligonucleotide is conjugated to an arginine-richpeptide.

The compounds may be administered by intravenous or subcutaneousinjection to the subject, at a dose between 1-5 or 1-20 mg/kg bodyweight antisense compound, and the administering step may be continuedat regular intervals of every two weeks to three months. The subject maybe monitored during the treatment for improvement in muscle performance,heart conduction properties, and/or for a reduction in serum creatinekinase.

Certain embodiments include antisense compounds for treating myotonicdystrophy type 2 (DM2), comprising a morpholino antisenseoligonucleotide of 9 bases, where the 9 bases are complementary topolyCCUG repeats in the first intron region of zinc finger protein 9(ZNF9) pre-mRNA. Also included are methods of treating myotonicdystrophy DM1 in a mammalian subject, comprising administering to thesubject, a morpholino antisense oligonucleotide of 9 bases, where the 9bases are complementary to polyCCUG repeats in the first intron regionof zinc finger protein 9 (ZNF9) pre-mRNA, and optionally repeating saidadministering at least once every one week to 3 months.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1A-C show exemplary structures of a phosphorodiamidate-linkedmorpholino oligomer (PMO), a peptide-conjugated PMO (PPMO), and apeptide-conjugated PMO having cationic intersubunit linkages (PPMO+),respectively. Though multiple cationic linkage types are illustrated inFIG. 1C, a PMO+ or PPMO+ oligomer will typically include just one typeof cationic linkage.

DETAILED DESCRIPTION Definitions

The terms below, as used herein, have the following meanings, unlessindicated otherwise:

The terms “cell penetrating peptide” or “CPP” are used interchangeablyand refer to cationic cell penetrating peptides, also called transportpeptides, carrier peptides, or peptide transduction domains. Examples ofcell-penetrating peptides include arginine-rich peptides. The peptides,as shown herein, typically have the capability of inducing cellpenetration within 100% of cells of a given cell culture population andallow macromolecular translocation within multiple tissues in vivo uponsystemic administration.

The terms “antisense oligomer” or “antisense oligonucleotide” or“oligonucleotide” are used interchangeably and refer to a sequence ofcyclic subunits, each bearing a base-pairing moiety, linked byintersubunit linkages that allow the base-pairing moieties to hybridizeto a target sequence in a nucleic acid (typically an RNA) byWatson-Crick base pairing, to form a nucleic acid:oligomer heteroduplexwithin the target sequence. The cyclic subunits are based on ribose oranother pentose sugar or, in a preferred embodiment, a morpholino group(see description of morpholino oligomers below). The oligomer may haveexact or near sequence complementarity to the target sequence;variations in sequence near the termini of an oligomer are generallypreferable to variations in the interior.

In one aspect of the invention, for the treatment of DM1, the antisenseoligonucleotide is complementary to at least 8, optionally 9-12 or morecontiguous bases in polyCUG repeats within the 3′ UTR regions of thetranscript for dystrophia myotonica protein kinase (DMPK) in musclecells, and is designed to bind by hybridization to these repeats,blocking binding of splice-associated proteins, such as one or moremuscleblind family proteins, e.g., MBNL1, or CUGBP to the transcript.The oligonucleotide may be said to be “directed to” or “targetedagainst” 3′UTR polyCUG repeats with which it hybridizes. The targetsequence may include a polyCUG region of at least 8 contiguous bases,preferably at least 9-25, and up to 40 bases or more.

In another aspect of the invention, for the treatment of DM2, theantisense oligonucleotide is complementary to at least 8, optionally9-12 or more contiguous bases in polyCUG repeats within intron 1 of thepre-mRNA transcript for zinc finger protein 9 (ZNF9) in muscle cells,and is designed to bind by hybridization to these repeats, blockingbinding of splice-associated proteins, such as one or more muscleblindfamily proteins, e.g., MBNL1, or CUGBP to the pre-mRNA transcript or theexcised intron 1 resulting from ZNF9 pre-mRNA processing. Theoligonucleotide may be said to be “directed to” or “targeted against”polyCCUG repeats with which it hybridizes. The target sequence mayinclude a polyCCUG region of at least 8 contiguous bases, preferably atleast 9-25, and up to 40 bases or more.

Specific embodiments include 9 base antisense oligomers such as PMO,PMO+, PPMO, or PPMO+ antisense oligonucleotides/compounds that are fullycomplementary to polyCUG repeats within the 3′ UTR regions of the RNAtranscript for DMPK, and antisense oligonucleotides/compounds that arefully complementary to polyCCUG repeats within intron 1 of the pre-mRNAtranscript for ZNF9. Examples include the antisense oligomers of SEQ IDNOS:1, 5, 9, and 15-18 targeted to polyCUG repeats, and SEQ ID NOS: 19,21, 23, 26-29 targeted to polyCCUG repeats.

The terms “morpholino oligomer” or “PMO” (phosphoramidate- orphosphorodiamidate morpholino oligomer) refer to an oligonucleotidecomposed of morpholino subunit structures, where (i) the structures arelinked together by phosphorus-containing linkages, one to three atomslong, preferably two atoms long, and preferably uncharged or cationic,joining the morpholino nitrogen of one subunit to a 5′ exocyclic carbonof an adjacent subunit, and (ii) each morpholino ring bears a purine orpyrimidine base-pairing moiety effective to bind, by base specifichydrogen bonding, to a base in a polynucleotide. See, for example, thestructure in FIG. 1A, which shows a preferred phosphorodiamidate linkagetype. Variations can be made to this linkage as long as they do notinterfere with binding or activity. For example, the oxygen attached tophosphorus may be substituted with sulfur (thiophosphorodiamidate). The5′ oxygen may be substituted with amino or lower alkyl substitutedamino. The pendant nitrogen attached to phosphorus may be unsubstituted,monosubstituted, or disubstituted with (optionally substituted) loweralkyl. See also the discussion of cationic linkages below. The purine orpyrimidine base pairing moiety is typically adenine, cytosine, guanine,uracil, thymine or inosine. The synthesis, structures, and bindingcharacteristics of morpholino oligomers are detailed in U.S. Pat. Nos.5,698,685, 5,217,866, 5,142,047, 5,034,506, 5,166,315, 5,521,063, and5,506,337, and PCT Pubn. No. WO 2008036127 (cationic linkages), all ofwhich are incorporated herein by reference.

An “amino acid subunit” or “amino acid residue” can refer to an α-aminoacid residue (—CO—CHR—NH—) or a β- or other amino acid residue (e.g.—CO—(CH₂)_(n)CHR—NH—), where R is a side chain (which may includehydrogen) and n is 1 to 6, preferably 1 to 4.

The term “naturally occurring amino acid” refers to an amino acidpresent in proteins found in nature. The term “non-natural amino acids”refers to those amino acids not present in proteins found in nature,examples include beta-alanine (β-Ala), 6-aminohexanoic acid (Ahx) and6-aminopentanoic acid.

A “marker compound” refers to a detectable compound attached to atransport peptide for evaluation of transport of the resulting conjugateinto a cell. The compound may be visually or spectrophotometricallydetected, e.g. a fluorescent compound or fluorescently labeled compound,which may include a fluorescently labeled oligomer. Preferably, themarker compound is a labeled or unlabeled antisense oligomer. In thiscase, detection of transport involves detection of a product resultingfrom modulation of splicing and/or transcription of a nucleic acid by anantisense oligomeric compound. Exemplary methods, such as a splicecorrection assay or exon skipping assay, are described in Materials andMethods below.

An “effective amount” or “therapeutically effective amount” refers to anamount of therapeutic compound, such as an antisense oligomer,administered to a mammalian subject, either as a single dose or as partof a series of doses, which is effective to produce a desiredtherapeutic effect.

“Treatment” of an individual (e.g. a mammal, such as a human) or a cellis any type of intervention used in an attempt to alter the naturalcourse of the individual or cell. Treatment includes, but is not limitedto, administration of a pharmaceutical composition, and may be performedeither prophylactically or subsequent to the initiation of a pathologicevent or contact with an etiologic agent.

The terms “antisense compound” or “compound” or “conjugate compound”include stand-alone antisense oligonucleotides (e.g., PMO, PMO+), andcompounds formed by conjugating a cell-penetrating peptide (e.g.,arginine-rich peptide) to an antisense oligonucleotide (e.g., PPMO,PPMO+). Examples of arginine-rich peptides include SEQ ID NOS:30-44,including the (RXRR(X/B)R)₂XB (SEQ ID NO:55) cell-penetrating peptides,which can be conjugated, for example, to an oligonucleotide targetedagainst a region of polyCUG or polyCCUG repeats.

“Systemic administration” of a compound refers to administration, suchas intravenous (iv) subcutaneous (subQ), intramuscular (IM), andintraperitoneal (IP) that delivers the compound directly into thebloodstream.

A systemically administered antisense oligonucleotide can be targeted,for example, to heart muscle tissue by conjugation to the CPP (RXRRBR)₂(SEQ ID NO:42) with an XB linkage, or other cell-penetrating peptide. Incertain instances, the compound, when administered systemically to a DM1subject in accordance with the method herein, produces a measurableimprovement in heart muscle performance and/or improvement in conductionproperties of the heart, as measured by known methods.

Structural Features of Transport Peptides

Exemplary cell-penetrating peptides that can employed in the inventioninclude a class of a transport peptide having 8 to 30 amino acidresidues in length and consisting of subsequences selected from thegroup consisting of RXR, RX, RB, and RBR; where R is arginine (which mayinclude D-arginine, represented in the sequences herein by r), B isβ-alanine, and each X is independently —C(O)—(CHR¹)_(n)—NH—, where n is4-6 and each R¹ is independently H or methyl, such that at most two R¹'sare methyl. Preferably, each R¹ is hydrogen. These peptides have thegeneric formula (RXRR(B/X)R)₂XB (SEQ ID NO:55), where R is arginine; Bis β-alanine; and each X is —C(O)—(CH₂)_(n)—NH—, where n is 4-6,preferably 6, and include both (RXRRBR)₂ (SEQ ID NO:42) with an XBlinkage, and (RXRRXR)₂ (SEQ ID NO:40) with an XB linkage, and where R isarginine; B is β-alanine; and each X is —C(O)—(CH₂)_(n)—NH—, where n is4-6. As discussed below, these peptides have been discovered toselectively target an oligonucleotide, including a PMO, to muscletissue, including heart muscle tissue.

Table 1 below includes certain transport peptides in this class thathave been evaluated, in conjugation with suitable antisenseoligonucleotides, for their ability to selectively target varioustissues, including heart and skeletal muscle. See, e.g., U.S.application Ser. No. 12/493,140, incorporated by reference in itsentirety. The peptides have been evaluated for cellular uptake, asdetermined by flow cytometry; for antisense activity, as determined by asplice correction assay (Kang, Cho et al. 1998); and for cellulartoxicity, as determined by MTT cell viability, propidium iodide membraneintegrity and hemolysis assays, and microscopic imaging, and theiruptake and functional activity in muscle tissue relative to a variety ofnon-muscle tissue were compared. The (RXRRXR)₂ peptide (SEQ ID NO:40)with an XB linkage was among the most active in antisense activity, asdetermined by the splice correction assay, both in the presence andabsence of added serum. Both (RXRR(B/X)R)₂XB (SEQ ID NO:55) peptideswere effective in selectively targeting oligonucleotides to heart andskeletal tissue, while showing relatively low-level targeting to avariety of other tissues, including mammary gland tissue, ovary/prostate(particularly (RXRRXR)₂ (SEQ ID NO:40) with an XB linkage), and brain.Embodiments of the present invention may employ any one or more of thesecell-penetrating or arginine-rich peptides.

TABLE 1 Cell-Penetrating Peptides SEQ Name ID (Designation) SequenceNO.^(a) rTAT RRRQRRKKR 30 Tat RKKRRQRRR 31 R₉F₂ RRRRRRRRRFF 32 R₅F₂R₄RRRRRFFRRRR 33 R₄ RRRR 34 R₅ RRRRR 35 R₆ RRRRRR 36 R₇ RRRRRRR 37 R₈RRRRRRRR 38 R₉ RRRRRRRRR 39 (RAhxR)₄; RAhxRRAhxRRAhxRRAhxR 40 (P007)(RAhxR)₅; RAhxRRAhxRRAhxRRAhxRRAhxR 41 (CP04057) (RAhxRRBR)₂;RAhxRRBRRAhxRRBR 42 (CP06062) (RAR)₄F₂ RARRARRARRARFFC 43 (RGR)₄F₂RGRRGRRGRRGRFFC 44 ^(a)Sequences assigned to SEQ ID NOs do not includethe linkage portion (e.g., C, G, Ahx, B, AhxB where Ahx and B refer to6-aminohexanoic acid and beta-alanine, respectively).Therapeutic Applications

The phosphorodiamidate morpholino oligomers (e.g., PMO, PMO+) and otherantisense oligomers described herein are useful for treating myotonicdystrophy type 1 (DM1), and the conjugate compounds (e.g., PPMO, PPMO+)of the present invention are further useful for targeting and deliveringthese antisense oligomers across both the cell and nuclear membranes tothe nucleus of muscle cells in skeletal and heart muscle tissue, byexposing the cell to an antisense oligomer or conjugate comprising theoligomer covalently linked to a carrier peptide, as described herein.

Treatment of Myotonic Dystrophy.

As the name of the disorder implies, the characteristic clinicalmanifestation in DM is myotonia (muscle hyperexcitability) and muscledegeneration. Affected individuals will also develop insulin resistance,cataracts, heart conduction defects, testicular atrophy,hypogammaglobulinemia and sleep disorders. Symptoms of DM can manifestin the adult or in childhood. The childhood onset form of the disease isoften associated with mental retardation. In addition, there is a formof the disease referred to as congenital myotonic dystrophy. This latterform of the disease is frequently fatal and is seen almost exclusivelyin children born of mothers who themselves are mildly affected by thedisease. In congenital DM the facial manifestations are distinctive dueto bilateral facial palsy and marked jaw weakness. Many infants withcongenital DM die due to respiratory insufficiency before a properdiagnosis of the disease is made.

DM1 initially involves the distal muscles of the extremities and only asthe disease progresses do proximal muscles become affected. In addition,muscles of the head and neck are affected early in the course of thedisease. Weakness in eyelid closure, limited extraocular movement andptosis results from involvement of the extraocular muscles. Manyindividuals with DM1 exhibit a characteristic “haggard” appearance thatis the result of atrophy of the masseters (large muscles that raise andlower the jaw), sternocleidomastoids (large, thick muscles that passobliquely across each side of the neck and contribute to arm movement)and the temporalis muscle (muscle involved in chewing).

Treatment of DM1, in accordance with general embodiments of theinvention, may comprise, for example: (i) administering to the subjectwith DM1, an antisense compound comprising an antisense oligonucleotidehaving 8-30 bases, with at least 8 contiguous bases being complementaryto the polyCUG repeats in the 3′UTR region of dystrophia myotonicaprotein kinase (DMPK) mRNA in DM1 and optionally conjugated to theoligonucleotide, a cell-penetrating peptide, and (ii) optionallyrepeating the compound administration at least once every one week toonce every three months or longer. Examples of cell-penetrating peptidesinclude the peptides of SEQ ID NOS:30-44. In specific embodiments, thecell-penetrating peptide may have the sequence (RXRR(B/X)R)₂XB (SEQ IDNO:55), where R is arginine; B is 3-alanine; and each X is—C(O)—(CH₂)_(n)—NH—, where n is 4-6.

Treatment of DM1, in accordance with specific embodiments of theinvention, may comprise: (i) administering to the subject with DM1 a9-base morpholino antisense oligonucleotide, where the 9 bases arecomplementary to polyCUG repeats in the 3′UTR region of dystrophiamyotonica protein kinase (DMPK) mRNA, and (ii) optionally repeating saidadministering at least once every one week to 3 months. The morpholinoantisense oligomer may be a phosphorodiamidate morpholinooligonucleotide (PMO), and/or it may be a PMO where at least one and upto about 1 per every 2 intersubunit linkage(s) contains a pendantcationic group, such as an optionally piperazino group (PMO+). The PMOor PMO+ compound may be optionally conjugated to a cell-penetratingpeptide, such as an arginine-rich peptide (e.g., PPMO, PPMO+).

The compound is preferably administered by intravenous or subcutaneousinjection to the subject, at a dose between 1-5 or 1-20 mg/kg bodyweight antisense compound, at a dosing schedule of once a month to onceevery 2-3 months. For subQ administration, the dose required may beroughly twice that for IV administration. During the course oftreatment, the patient is monitored for improvement or stabilization ofmuscle performance, improvement in heart conduction properties and/orreduction in serum reduction in serum creatine kinase. Because myotonicdystrophy is a chronic disease, the treatment method will be appliedover the subject's lifetime, with dose adjustments being made during thetreatment period to achieve a desired level of muscle function and toaccommodate patient growth.

The treatment methods offer a number of important advantages overearlier proposed antisense methods of treating DM1. First, targeting,uptake and antisense activity of the antisense compounds describedherein into skeletal muscle, heart muscle, or both, is efficient. Thisallows effective treatment with relatively modest compound doses, e.g.,in the range 1-5 mg/kg subject weight. Second, little or no compoundtoxicity has been observed, as evidenced, for example, by nomicroscopically observable increases in muscle damage, inflammatorycellular infiltrates, or necrotic fibers in muscles injected with PPMOsand/or PMOs. Finally, in certain instances, the effect of a single dosemay be effective for up to three months or more, allowing the patient tobe effectively treated by dosing at intervals of no less than one month,and up to 3 months or more between successive treatments.

Combination with Homing Peptides

The antisense oligonucleotides and conjugate compounds of the inventionmay be used in conjunction with homing peptides selective for the targettissue, to further enhance muscle-specific delivery. An example of thisapproach can be found in the application of muscle-binding peptides(Samoylova and Smith, 1999; Vodyanoy et al., U.S. Appn. Pubn. No.20030640466) coupled to antisense oligomers designed to be therapeutictreatments for Duchenne muscular dystrophy (DMD) (Gebski, Mann et al.2003; Alter, Lou et al. 2006) (PCT Pubn. No. WO2006000057). Theheptapeptide sequence ASSLNIA (SEQ ID NO:45) has enhanced in vivoskeletal and cardiac muscle binding properties, as described bySamoylova and Smith. As a further example, a pancreas-homing peptide,CRVASVLPC (SEQ ID NO:56), mimics the natural prolactin receptor ligand(Kolonin, Sun et al. 2006).

An exemplary dual peptide molecule has a cell penetrating peptide to oneterminus, e.g. at the 5′ end of the antisense oligomer, as describedherein, and a homing peptide coupled to the other terminus, i.e. the 3′terminus. The homing peptide localizes the peptide-conjugated PMO to thetarget tissue, where the cell-penetrating peptide moiety effectstransport into the cells of the tissue.

Alternatively, a preferred exemplary dual peptide molecule would haveboth a homing peptide (HP) and cell-penetrating peptide (CPP) conjugatedto one end, e.g. the 5′ terminus of the antisense oligomer, in either aHP-CPP-PMO configuration or, more preferably, a CPP-HP-PMOconfiguration.

TABLE 2 Examples of Muscle-specific Homing Peptides (HP) SEQPeptide Sequence ID Target Tissue (NH₂ to COOH) NO. Skeletal  ASSLNIA 45Muscle-SMP1 SMP2 SLGSFP 46 SMP3 SGASAV 47 SMP4 GRSGAR 48 SMP5TARGEHKEEELI 49 Cardiac  WLSEAGPVVTVRALRGTGSW 50 Muscle-CMP1 CMP2VTVRALRGTSW 51 CMP3 VVTVRALRGTGSW 52 CMP4 CRPPR 53 CMP5 SKTFNTHPQSTP 54CRVASVLPC 56Peptide-Antisense Oligomer Conjugate CompositionsConjugates for Specific Muscle Treatments

Therapeutic conjugates comprising selected transport peptide sequencesare also provided by the invention. These include conjugates comprisinga carrier peptide (RXRR(B/X)R)₂XB (SEQ ID NO:55), as described herein,conjugated to an oligonucleotide, e.g., PMO, designed for therapeuticaction within muscle tissue. Also included are conjugates comprising anoligonucleotide conjugated to any one of SEQ ID NOS:30-44.

The conjugates may further comprise a targeting moiety effective to bindto tissue specific receptors of a target tissue type, linked to thetherapeutic compound or, preferably, to another terminus of the carrierpeptide. In particularly preferred embodiments, a homing peptide such asdescribed above is conjugated to therapeutic compound or to thecell-penetrating peptide.

For use in treating myotonic dystrophy DM1, the conjugate compound maycomprise an antisense oligonucleotide, having 8-30 bases, preferably 9bases, with at least 8 or 9 or more contiguous bases being complementaryto the polyCUG repeats in the 3′UTR region of dystrophia myotonicaprotein kinase (DMPK) mRNA, and conjugated to the oligonucleotide, acell-penetrating peptide of any one of SEQ ID NOS:30-44, including, forexample, a peptide having the sequence (RXRR(B/X)R)₂XB (SEQ ID NO:55),where R is arginine; B is β-alanine; and each X is —C(O)—(CH₂)_(n)—NH—,where n is 4-6. Such compounds are effective to selectively block thesequestration of muscleblind-like 1 protein (MBNL1) and/or CUGBP inheart and quadricep muscle in a myotonic dystrophy animal model.

Morpholino Oligomers Having Cationic and Other Intersubunit Linkages

In preferred embodiments, as noted above, the antisense oligomer is aphosphorodiamidate morpholino oligonucleotide (PMO). Certain PMOs mayinclude between about 10-50% or 20-50% positively charged or cationicbackbone linkages, as described below and further in WO/2008/036127,which is incorporated by reference.

Certain cationic PMOs (e.g., PMO+) include morpholino oligomers in whichat least one intersubunit linkage between two consecutive morpholinoring structures contains a pendant cationic group. The pendant groupbears a distal nitrogen atom that can bear a positive charge at neutralor near-neutral (e.g., physiological) pH. Examples are shown in FIGS.1B-C.

The intersubunit linkages in these oligomers are preferablyphosphorus-containing linkages, having the structure:

where

-   W is S or O, and is preferably O,-   X=NR¹R² or OR⁶,-   Y=O or NR⁷,

and each said linkage in the oligomer is selected from:

(a) uncharged linkage (a), where each of R¹, R², R⁶ and R⁷ isindependently selected from hydrogen and lower alkyl;

(b1) cationic linkage (b1), where X=NR¹R² and Y=O, and NR¹R² representsan optionally substituted piperazino group, such thatR¹R²=—CHRCHRN(R³)(R⁴)CHRCHR—, where

each R is independently H or CH₃,

R⁴ is H, CH₃, or an electron pair, and

R³ is selected from H, lower alkyl, e.g. CH₃, C(═NH)NH₂,Z-L-NHC(═NH)NH₂, and {C(O)CHR′NH}_(m)H, where: Z is C(O) or a directbond, L is an optional linker up to 18 atoms in length, preferably up to12 atoms, and more preferably up to 8 atoms in length, having bondsselected from alkyl, alkoxy, and alkylamino, R′ is a side chain of anaturally occurring amino acid or a one- or two-carbon homolog thereof,and m is 1 to 6, preferably 1 to 4;

(b2) cationic linkage (b2), where X=NR′R² and Y=O, R¹=H or CH₃, andR²=LNR³R⁴R⁵, where L, R³, and R⁴ are as defined above, and R⁵ is H,lower alkyl, or lower (alkoxy)alkyl; and

(b3) cationic linkage (b3), where Y=NR⁷ and X=OR⁶, and R⁷=LNR³R⁴R⁵,where L, R³, R⁴ and R⁵ are as defined above, and R⁶ is H or lower alkyl;

and at least one said linkage is selected from cationic linkages (b1),(b2), and (b3).

Preferably, the oligomer includes at least two consecutive linkages oftype (a) (i.e. uncharged linkages). In further embodiments, at least 5%of the linkages in the oligomer are cationic linkages (i.e. type (b1),(b2), or (b3)); for example, 10% to 80%, 10% to 50%, or 10% to 35% ofthe linkages may be cationic linkages.

In one embodiment, at least one linkage is of type (b1), where,preferably, each R is H, R⁴ is H, CH₃, or an electron pair, and R³ isselected from H, lower alkyl, e.g. CH₃, C(═NH)NH₂, andC(O)-L-NHC(═NH)NH₂. The latter two embodiments of R³ provide a guanidinomoiety, either attached directly to the piperazine ring, or pendant to alinker group L, respectively. For ease of synthesis, the variable Z inR³ is preferably C(O) (carbonyl), as shown.

The linker group L, as noted above, contains bonds in its backboneselected from alkyl (e.g. —CH₂—CH₂—), alkoxy (—C—O—), and alkylamino(e.g. —CH₂—NH—), with the proviso that the terminal atoms in L (e.g.,those adjacent to carbonyl or nitrogen) are carbon atoms. Althoughbranched linkages (e.g. —CH₂—CHCH₃—) are possible, the linker ispreferably unbranched. In one embodiment, the linker is a hydrocarbonlinker. Such a linker may have the structure —(CH₂)_(n)—, where n is1-12, preferably 2-8, and more preferably 2-6.

The use of embodiments of linkage types (b1), (b2) and (b3) above tolink morpholino subunits may be illustrated graphically as follows:

Preferably, all cationic linkages in the oligomer are of the same type;i.e. all of type (b1), all of type (b2), or all of type (b3). Thebase-pairing moieties Pi may be the same or different, and are generallydesigned to provide a sequence which binds to a target nucleic acid.

In further embodiments, the cationic linkages are selected from linkages(b1′) and (b1″) as shown below, where (b1′) is referred to herein as a“Pip” linkage and (b1″) is referred to herein as a “GuX” linkage:

In the structures above, W is S or O, and is preferably O; each of R¹and R² is independently selected from hydrogen and lower alkyl, and ispreferably methyl; and A represents hydrogen or a non-interferingsubstituent on one or more carbon atoms in (b1′) and (b1″). Preferably,the ring carbons in the piperazine ring are unsubstituted; however, theymay include non-interfering substituents, such as methyl or fluorine.Preferably, at most one or two carbon atoms is so substituted.

In further embodiments, at least 10% of the linkages are of type (b1′)or (b1″); for example, 20% to 80%, 20% to 50%, or 20% to 30% of thelinkages may be of type (b1′) or (b1″).

In other embodiments, the oligomer contains no linkages of the type(b1′) above. Alternatively, the oligomer contains no linkages of type(b1) where each R is H, R³ is H or CH₃, and R⁴ is H, CH₃, or an electronpair.

Oligomers having any number of cationic linkages can be used, includingfully cationic-linked oligomers. Preferably, however, the oligomers arepartially charged, having, for example, 5, 10, 20, 30, 40, 50, 60, 70,80 or 90 percent cationic linkages. In selected embodiments, about 10 to80, 20 to 80, 20 to 60, 20 to 50, 20 to 40, or about 20 to 35 percent ofthe linkages are cationic.

In one embodiment, the cationic linkages are interspersed along thebackbone. The partially charged oligomers preferably contain at leasttwo consecutive uncharged linkages; that is, the oligomer preferablydoes not have a strictly alternating pattern along its entire length.

Also considered are oligomers having blocks of cationic linkages andblocks of uncharged linkages; for example, a central block of unchargedlinkages may be flanked by blocks of cationic linkages, or vice versa.In one embodiment, the oligomer has approximately equal-length 5′, 3′and center regions, and the percentage of cationic linkages in thecenter region is greater than about 50%, preferably greater than about70%.

Oligomers for use in antisense applications generally range in lengthfrom about 10 to about 40 subunits, more preferably about 15 to 25subunits. For example, a cationic oligomer having 19-20 subunits, auseful length for an antisense oligomer, may ideally have two to seven,e.g. four to six, or three to five, cationic linkages, and the remainderuncharged linkages. An oligomer having 14-15 subunits may ideally havetwo to five, e.g. 3 or 4, cationic linkages and the remainder unchargedlinkages. Specific examples include a 9 subunit oligomer with about 1,2, or 3 cationic linkages, and the remainder uncharged linkages.

Each morpholino ring structure supports a base pairing moiety, to form asequence of base pairing moieties which is typically designed tohybridize to a selected antisense target in a cell or in a subject beingtreated. The base pairing moiety may be a purine or pyrimidine found innative DNA or RNA (A, G, C, T, or U) or an analog, such as hypoxanthine(the base component of the nucleoside inosine) or 5-methyl cytosine.

As noted above, the substantially uncharged oligonucleotide may bemodified to include one or more charged linkages, e.g. up to about 1 perevery 2-5 uncharged linkages, typically 3-5 per every 10 unchargedlinkages. Optimal improvement in antisense activity is seen where up toabout half of the backbone linkages are cationic. Some, but not maximumenhancement is typically seen with a small number e.g., 10-20% cationiclinkages; where the number of cationic linkages exceeds 50-60%, thesequence specificity of the antisense binding to its target may becompromised or lost.

The enhancement seen with added cationic backbone charges may, in somecase, be further enhanced by distributing the bulk of the charges closeof the “center-region” backbone linkages of the antisenseoligonucleotide, e.g., in a 20-mer oligonucleotide with 8 cationicbackbone linkages, having 70%-100% of these charged linkages localizedin the 10 centermost linkages.

Other Oligomer Types

Delivery of alternative antisense chemistries can also benefit from thedisclosed carrier peptide. Specific examples of other antisensecompounds useful in this invention include those in which at least one,or all, of the internucleotide bridging phosphate residues are modifiedphosphates, such as methyl phosphonates, phosphorothioates, orphosphoramidates. Also included are molecules wherein at least one, orall, of the nucleotides contains a 2′ lower alkyl moiety (e.g., C1-C4,linear or branched, saturated or unsaturated alkyl, such as methyl,ethyl, ethenyl, propyl, 1-propenyl, 2-propenyl, or isopropyl).

In other oligonucleotide mimetics, both the sugar and theinternucleoside linkage, i.e., the backbone, of the nucleotide units aremodified. The base units are maintained for hybridization with anappropriate nucleic acid target compound. One such oligomeric compound,an oligonucleotide mimetic that has been shown to have excellenthybridization properties, is referred to as a peptide nucleic acid(PNA). In PNA compounds, the sugar-phosphate backbone of anoligonucleotide is replaced with an amide containing backbone, inparticular an aminoethylglycine backbone.

Modified oligonucleotides may be classified as “chimeric,” e.g.,containing at least one region wherein the oligonucleotide is modifiedso as to confer increased resistance to nuclease degradation orincreased cellular uptake, and an additional region for increasedbinding affinity for the target nucleic acid.

EXAMPLES

The following examples are intended to illustrate but not to limit theinvention.

Example 1 PMO, PMO+, PPMO and PPMO+ Consisting of (CAG)n Repeats ReverseMolecular and Physiological Manifestations of DM1 in a Mouse Model

To determine whether antisense compositions described herein (e.g., SEQID NOs: 1-18) can influence in vivo expanded CUG (CUGexp) repeatinteractions with MBNL1 splicing factor, their effects can be examinedin a transgenic mouse model of DM1. The antisense oligonucleotides andconjugates shown in Table A below can be manufactured according toroutine techniques and then tested in this transgenic mouse model ofDM1.

TABLE A PMO, PMO+, PPMO, and PPMO+ agents targeted to polyCUG repeats in the 3′UTR region of dystrophia myotonica protein kinase (DMPK).Sample Name Sequence 5′End 3′End CAG 9mer CAG CAG CAG (SEQ ID NO: 1) EG3H CAG 9mer-B CAG CAG CAG (SEQ ID NO: 1) EG3 CP06062 CAG 9mer-R9F2CAG CAG CAG (SEQ ID NO: 1) EG3 R9F2 CAG 9mer-rTatCAG CAG CAG (SEQ ID NO: 1) EG3 rTat CAG 12merCAG CAG CAG CAG (SEQ ID NO: 2) EG3 H CAG 12mer-BCAG CAG CAG CAG (SEQ ID NO: 2) EG3 CP06062 CAG 15merCAG CAG CAG CAG CAG (SEQ ID NO: 3) EG3 H CAG 15mer-BCAG CAG CAG CAG CAG (SEQ ID NO: 3) EG3 CP06062 CAG 18merCAG CAG CAG CAG CAG CAG (SEQ ID NO: 4) EG3 H CAG 18mer-BCAG CAG CAG CAG CAG CAG (SEQ ID NO: 4) EG3 CP06062 AGC 9merAGC AGC AGC (SEQ ID NO: 5) EG3 H AGC 9mer-B AGC AGC AGC (SEQ ID NO: 5)EG3 CP06062 AGC 12mer AGC AGC AGC AGC (SEQ ID NO: 6) EG3 H AGC 12mer-BAGC AGC AGC AGC (SEQ ID NO: 6) EG3 CP06062 AGC 15merAGC AGC AGC AGC AGC (SEQ ID NO: 7) EG3 H AGC 15mer-BAGC AGC AGC AGC AGC (SEQ ID NO: 7) EG3 CP06062 AGC 18merAGC AGC AGC AGC AGC AGC (SEQ ID NO: 8) EG3 H AGC 18mer-BAGC AGC AGC AGC AGC AGC (SEQ ID NO: 8) EG3 CP06062 GCA 9merGCA GCA GCA (SEQ ID NO: 9) EG3 H GCA 9mer-B GCA GCA GCA (SEQ ID NO: 9)EG3 CP06062 GCA 12mer GCA GCA GCA GCA (SEQ ID NO: 10) EG3 H GCA 12mer-BGCA GCA GCA GCA (SEQ ID NO: 10) EG3 CP06062 GCA 15merGCA GCA GCA GCA GCA (SEQ ID NO: 11) EG3 H GCA 15mer-BGCA GCA GCA GCA GCA (SEQ ID NO: 11) EG3 CP06062 GCA 18merGCA GCA GCA GCA GCA GCA (SEQ ID NO: 12) EG3 H GCA 18mer-BGCA GCA GCA GCA GCA GCA (SEQ ID NO: 12) EG3 CP06062 AGC 25merAGC AGC AGC AGC AGC AGC AGC AGC A EG3 H (SEQ ID NO: 13) AGC 25mer-BAGC AGC AGC AGC AGC AGC AGC AGC A EG3 CP06062 (SEQ ID NO: 13) CAG 25merCAG CAG CAG CAG CAG CAG CAG CAG C EG3 H (SEQ ID NO: 14) CAG 25mer-BCAG CAG CAG CAG CAG CAG CAG CAG C EG3 CP06062 (SEQ ID NO: 14)CAG 25mer-R9F2 CAG CAG CAG CAG CAG CAG CAG CAG C EG3 R9F2(SEQ ID NO: 14) CAG 25mer-rTat CAG CAG CAG CAG CAG CAG CAG CAG C EG3rTat (SEQ ID NO: 14) CAG 9mer+ C+AG C+AG C+AG (SEQ ID NO: 15) EG3 HCAG 9mer+B C+AG C+AG C+AG (SEQ ID NO: 15) EG3 CP06062 CAG 9mer+C+AG CAG CAG (SEQ ID NO: 16) EG3 H CAG 9mer+CAG CAG C+AG (SEQ 1D NO: 17) EG3 H CAG 9mer+CAG C+AG CAG (SEQ ID NO: 18) EG3 H * The linkage(s) between theoligonucleotide and the cell-penetrating peptide can included a varietyof linkages, but preferred linkages are C, AhxB, G, and B.

HSA^(LR) transgenic mice express human skeletal actin transcripts thathave (CUG) 250 inserted in the 3′ UTR (Mankodi, Logigian et al. 2000).These mice accumulate CUGexp RNA and MBNL1 protein in nuclear foci inskeletal muscle, a process that depends on CUGexp-MBNL1 interaction(Dansithong, Paul et al. 2005). The effect of antisense compositions ofthe present invention can be examined in their ability to block focidevelopment in muscle cells. PMO and PPMO can be delivered intravenouslyor intraperitoneally at doses ranging from 30 to 600 micrograms. Muscletissue can be examined 1-3 weeks later by fluorescence in situhybridization using probes that hybridize to the CUG repeat or tosequences flanking the repeat. Activity of any given compound can bemeasured by the magnitude of reduction of nuclear foci andredistribution of MBNL1 from a punctate pattern to diffuse localizationin the nucleus.

Compositions of the present invention can also reverse the biochemicalconsequences of MBNL1 sequestration. Accumulation of CUGexp RNA-MBNL1complexes in the foci results also in aberrant mis-splicing of severalgenes, namely, CIC-1, Serca-1, m-Titin, Tnnt3 and Zasp genes (Mulders,van den Broek et al. 2009). HSA^(LR) transgenic mice show alternativesplicing changes similar to those observed in human DM1 (Wheeler,Sobczak et al. 2009). DM1-affected, aberrantly spliced exons can beexamined in mice treated with compositions of the invention to determinewhether alternative splicing is corrected at three weeks followinginjection of compositions of the present invention. Effects of PMO orPPMO treatment on aberrant splicing can be expected to persist for atleast fourteen weeks.

It is also expected that compositions of the present invention canrescue the physiological effects of DM1 (myotonia) and can be examinedby measuring the expression and function of chloride channel 1 (ClC-1)which is inactivated by mis-splicing in DM1 and the HSA^(LR) mousemodel. Myotonia can be measured through determination of delayed musclerelaxation and repetitive action potentials and are expected to improvein HSA^(LR) mice treated with compositions of the present invention.

Example 2 PMO, PPMOplus, PPMO AND PMO-X Consisting of (CCAG)n RepeatsReverse Molecular and Physiological Manifestations of DM2

To determine whether antisense compositions described herein (e.g., SEQID NOs: 19-29) can influence in vivo expanded CCUG (CCUGexp) repeatinteractions with MBNL1 splicing factor, their effects can be examinedin an analogous transgenic mouse model to that described above for DM1.The antisense oligonucleotides and conjugates shown in Table B below canbe manufactured according to routine techniques and then tested in thistransgenic mouse model of DM2. The expected experimental outcomes aresimilar to those described for DM1 in Example 1.

TABLE B PMO, PMO+, PPMO, and PPMO+ agents targeted to polyCCUG repeatsin the first intron of zinc finger protein 9 (ZNF9) pre-mRNA.Sample Name Sequence 5′End 3′End CAGG 9mer CAG GCA GGC (SEQ ID NO: 19)EG3 H CAGG 9mer-B CAG GCA GGC (SEQ ID NO: 19) EG3 CP06062 CAGG 9mer-R9F2CAG GCA GGC (SEQ ID NO: 19) EG3 R9F2 CCAG 9mer-rTatCAG GCA GGC (SEQ ID NO: 19) EG3 rTat CCAG 12merCAG GCA GGC AGG (SEQ ID NO: 20) EG3 H CCAG 12mer-BCAG GCA GGC AGG (SEQ ID NO: 20) EG3 CP06062 AGCC 9merAGG CAG GCA (SEQ ID NO: 21) EG3 H AGCC 9mer-BAGG CAG GCA (SEQ ID NO: 21) EG3 CP06062 AGCC 12merAGG CAG GCA GGC (SEQ ID NO: 22) EG3 H AGCC 12mer-BAGG CAG GCA GGC (SEQ ID NO: 22) EG3 CP06062 GCCA 9merGGC AGG CAG (SEQ ID NO: 23) EG3 H GCCA 9mer-BGGC AGG CAG (SEQ ID NO: 23) EG3 CP06062 GCCA 12merGGC AGG CAG GCA (SEQ ID NO: 24) EG3 H GCCA 12mer-BGGC AGG CAG GCA (SEQ ID NO: 24) EG3 CP06062 CAGG 24merCAG GCA GGC AGG CAG GCA GGC AGG EG3 H (SEQ ID NO: 25) CAGG 24mer-BCAG GCA GGC AGG CAG GCA GGC AGG EG3 CP06062 (SEQ ID NO: 25)CAGG 24mer-R9F2 CAG GCA GGC AGG CAG GCA GGC AGG EG3 R9F2 (SEQ ID NO: 25)CAGG 24mer-rTat CAG GCA GGC AGG CAG GCA GGC AGG EG3 rTat (SEQ ID NO: 25)CAGG 9mer+ C+AG GC+A GGC (SEQ ID NO: 26) EG3 H CAGG 9mer+BC+AG GC+A GGC (SEQ ID NO: 27) EG3 CP06062 CAGG 9mer+C+AG GCA GGC (SEQ ID NO: 28) EG3 H CAGG 9mer+CAG GC+A GGC (SEQ ID NO: 29) EG3 H * The linkage(s) between theoligonucleotide and the cell-penetrating peptide can included a varietyof linkages, but preferred linkages are C, AhxB, G, and B.

Although the invention has been described with respect to certainembodiments and examples, it will be appreciated that various changes,modifications, and additions may be made without departing from theclaimed invention.

REFERENCES

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Wheeler, T. M. and C. A. Thornton (2007). “Myotonic dystrophy:RNA-mediated muscle disease.” Curr Opin Neurol 20(5): 572-6.

SEQUENCE LISTING TABLE SEQ ID Sample Name Sequence NO: CAG 9merCAG CAG CAG  1 CAG 12mer CAG CAG CAG CAG  2 CAG 15merCAG CAG CAG CAG CAG  3 CAG 18mer CAG CAG CAG CAG CAG CAG  4 AGC 9merAGC AGC AGC  5 AGC 12mer AGC AGC AGC AGC  6 AGC 15merAGC AGC AGC AGC AGC  7 AGC 18mer AGC AGC AGC AGC AGC AGC  8 GCA 9merGCA GCA GCA  9 GCA 12mer GCA GCA GCA GCA 10 GCA 15merGCA GCA GCA GCA GCA 11 GCA 18mer GCA GCA GCA GCA GCA GCA 12 AGC 25merAGC AGC AGC AGC AGC AGC AGC AGC A 13 CAG 25merCAG CAG CAG CAG CAG CAG CAG CAG C 14 CAG 9mer+ C+AG C+AG C+AG 15CAG 9mer+ C+AG CAG CAG 16 CAG 9mer+ CAG CAG C+AG 17 CAG 9mer+CAG C+AG CAG 18 CAGG 9mer CAG GCA GGC 19 CAGG 12mer CAG GCA GGC AGG 20AGGC 9mer AGG CAG GCA 21 AGGC 12mer AGG CAG GCA GGC 22 GGCA 9merGGC AGG CAG 23 GGCA 12mer GGC AGG CAG GCA 24 CAGG 24merCAG GCA GGC AGG CAG GCA GGC AGG 25 CAGG 9mer+ C+AG GC+A GGC 26CAGG 9mer+B C+AG GC+A GGC 27 CAGG 9mer+ C+AG GCA GGC 28 CAGG 9mer+CAG GC+A GGC 29 rTAT RRRQRRKKR 30 Tat RKKRRQRRR 31 R₉F₂ RRRRRRRRRFF 32R₅F₂R₄ RRRRRFFRRRR 33 R₄ RRRR 34 R₅ RRRRR 35 R₆ RRRRRR 36 R₇ RRRRRRR 37R₈ RRRRRRRR 38 R₉ RRRRRRRRR 39 (RAhxR)₄; RAhxRRAhxRRAhxRRAhxR 40 (P007)(RAhxR)₅; RAhxRRAhxRRAhxRRAhxRRAhxR 41 (CP04057) (RAhxRRBR)₂;RAhxRRBRRAhxRRBR 42 (CP06062) (RAR)₄F₂ RARRARRARRARFFC 43 (RGR)₄F₂RGRRGRRGRRGRFFC 44 SMP1 ASSLNIA 45 SMP2 SLGSFP 46 SMP3 SGASAV 47 SMP4GRSGAR 48 SMP5 TARGEHKEEELI 49 CMP1 WLSEAGPVVTVRALRGTGSW 50 CMP2VTVRALRGTSW 51 CMP3 VVTVRALRGTGSW 52 CMP4 CRPPR 53 CMP5 SKTFNTHPQSTP 54(RXRR(X/B)R)₂XB 55 CRVASVLPC 56 *In SEQ ID NOS: 15-18 and 26-29, “+”refers to a cationic linkage, such as 1-piperazinyl.

It is claimed:
 1. An antisense conjugate, or a pharmaceuticallyacceptable salt thereof, comprising a phosphorodiamidate morpholinooligomer (PMO) of 8-30 bases comprising a sequence of at least 8contiguous bases that is complementary to the polyCUG repeats in the3′-UTR region of dystrophia myotonica protein kinase (DMPK) mRNA inmyotonic dystrophy type 1 (DM1), and a cell-penetrating peptide (CPP)conjugated to the oligomer, wherein the CPP is conjugated to theantisense oligomer with a linker, and wherein the CPP and linkertogether are of a formula selected from the group consisting of:

wherein R^(a) is H or acetyl.
 2. The antisense conjugate of claim 1, orpharmaceutically acceptable salt thereof, wherein the CPP and linkertogether are of the formula:


3. The antisense conjugate of claim 1, or pharmaceutically acceptablesalt thereof, wherein the CPP and linker together are of the formula:


4. The antisense conjugate of claim 1, or pharmaceutically acceptablesalt thereof, wherein the CPP and linker together are of the formula:


5. The antisense conjugate of claim 1, or pharmaceutically acceptablesalt thereof, wherein the CPP and linker together are of the formula:


6. The antisense conjugate of claim 1, or pharmaceutically acceptablesalt thereof, wherein the CPP and linker together are of the formula:


7. The antisense conjugate of claim 1, or pharmaceutically acceptablesalt thereof, wherein the CPP and linker together are of the formula:


8. The antisense conjugate of claim 1, or pharmaceutically acceptablesalt thereof, wherein the sequence is selected from SEQ ID NOs: 1-14. 9.An antisense conjugate, or a pharmaceutically acceptable salt thereof,comprising a phosphorodiamidate morpholino oligomer (PMO) of 8-30 basescomprising a sequence of at least 8 contiguous bases that iscomplementary to the polyCCUG repeats in the first intron of zinc fingerprotein 9 (ZNF9) mRNA in myotonic dystrophy type 2 (DM2), and acell-penetrating peptide (CPP) conjugated to the oligomer, wherein theCPP is conjugated to the antisense oligomer with a linker, and whereinthe CPP and linker together are of a formula selected from the groupconsisting of:

wherein R^(a) is H or acetyl.
 10. The antisense conjugate of claim 9, orpharmaceutically acceptable salt thereof, wherein the CPP and linkertogether are of the formula:


11. The antisense conjugate of claim 9, or pharmaceutically acceptablesalt thereof, wherein the CPP and linker together are of the formula:


12. The antisense conjugate of claim 9, or pharmaceutically acceptablesalt thereof, wherein the CPP and linker together are of the formula:


13. The antisense conjugate of claim 9, or pharmaceutically acceptablesalt thereof, wherein the CPP and linker together are of the formula:


14. The antisense conjugate of claim 9, or pharmaceutically acceptablesalt thereof, wherein the CPP and linker together are of the formula:


15. The antisense conjugate of claim 9, or pharmaceutically acceptablesalt thereof, wherein the CPP and linker together are of the formula:


16. The antisense conjugate of claim 9, or a pharmaceutically acceptablesalt thereof, wherein the sequence is selected from SEQ ID NOs: 19-25.17. A method of treating myotonic dystrophy type 1 (DM1) or myotonicdystrophy type 2 (DM2) in a mammalian subject in need thereof,comprising administering to the subject an effective amount of anantisense conjugate, or a pharmaceutically acceptable salt thereof,wherein the antisense conjugate or pharmaceutically acceptable saltthereof comprises: a phosphorodiamidate morpholino oligomer (PMO) of8-30 bases comprising a sequence of at least 8 contiguous bases that iscomplementary to the polyCUG repeats in the 3′-UTR region of dystrophiamyotonica protein kinase (DMPK) mRNA in DM1, and a cell-penetratingpeptide (CPP) conjugated to the oligomer, wherein the CPP is conjugatedto the antisense oligomer with a linker, and wherein the CPP and linkertogether are of a formula selected from the group consisting of:

wherein R^(a) is H or acetyl.
 18. The method of claim 17, wherein theCPP and linker together are of the formula:


19. The method of claim 17, wherein the CPP and linker together are ofthe formula:


20. The method of claim 17, wherein the CPP and linker together are ofthe formula:


21. The method of claim 17, wherein the CPP and linker together are ofthe formula:


22. The method of claim 17, wherein the CPP and linker together are ofthe formula:


23. The method of claim 17, wherein the CPP and linker together are ofthe formula:


24. The method of claim 17, wherein the sequence is selected from SEQ IDNOs: 1-14.
 25. A method of treating myotonic dystrophy type 2 (DM2) in amammalian subject in need thereof, comprising administering to thesubject an effective amount of an antisense conjugate, or apharmaceutically acceptable salt thereof, wherein the antisenseconjugate or pharmaceutically acceptable salt thereof comprises: aphosphorodiamidate morpholino oligomer (PMO) of 8-30 bases comprising asequence of at least 8 contiguous bases that is complementary to thepolyCCUG repeats in the first intron of zinc finger protein 9 (ZNF9)mRNA in DM2, and a cell-penetrating peptide (CPP) conjugated to theoligomer, wherein the CPP is conjugated to the antisense oligomer with alinker, and wherein the CPP and linker together are of a formulaselected from the group consisting of:

wherein R^(a) is H or acetyl.
 26. The method of claim 25, wherein theCPP and linker together are of the formula:


27. The method of claim 25, wherein the CPP and linker together are ofthe formula:


28. The method of claim 25, wherein the CPP and linker together are ofthe formula:


29. The method of claim 25, wherein the CPP and linker together are ofthe formula:


30. The method of claim 25, wherein the CPP and linker together are ofthe formula:


31. The method of claim 25, wherein the CPP and linker together are ofthe formula:


32. The method of claim 25, wherein the sequence is selected from SEQ IDNOs: 19-25.